1. Field of the Invention
The present invention relates to leg extension devices and, more particularly, to such devices as are removably attached to the legs of a user. More particularly, the present invention relates to a pair of stilts with articulating foot pads that provide enhanced maneuverability and stability to a user.
2. Description of the Prior Art
Recognizing physical limitations when compared to other animal life, mankind has longed to run faster, jump higher, and be taller than evolution has seemingly provided. Conceptually the latter appears the easiest to solve, using a pole extension to each leg. Such constructions are known as xe2x80x9cpegxe2x80x9d or xe2x80x9cpolexe2x80x9d (or sometimes xe2x80x9cChinesexe2x80x9d) stilts and they were of the earliest stilts designs.
Although simple in construction, users quickly appreciated the difference between a circumscribed, weight bearing surface and the human foot. Using pole stilts over the carefully prepared surfaces found in circuses is entirely different than attempting their use on gravel, on uneven surfaces, and where holes and like traps abound. Additionally, the lack of a stable base makes remaining stationary an exercise in balance, which is particularly a problem for those in construction, where their added height would be useful for ceiling and drywall installers.
An early attempt at providing stability envisioned the use of multiple supports, such as Hawk, U.S. Pat. No. 2,292,074, where four support feet are distributed under the foot support. The mobility issues of such a construction are readily apparent, and further efforts were required by stilts designers to better emulate the human foot.
A better attempt to simulate the stability and mobility provided by a human foot found its expression in the DURA-STILT(copyright) brand stilt design, the subject of U.S. Pat. Nos. 3,102,199 and 3,902,199 to Emmert. The early design provided a K-shaped support brace and two separate shoe plates identified as front and rear. The rear strut bore the majority of the load, with two diagonal pieces forming a forward lever that is attached to the rear strut at an intermediate location in a two-spring housing that permitted vertical movement within the rear strut.
The K-shaped support lever with the spring connection attempted to mimic the shifts in weight between the front and back of a human foot during various forms of locomotion. In a later improvement (U.S. Pat. No. 3,902,199), the forward K-brace was straightened into a front strut, and the spring mounting moved outside of the rear strut, to a location between the two struts. With a foot plate above and two base pads below, the hinged struts form a parallelogram simulation of human foot movement.
Although two base pads were in use, with a rigid footplate the base pads function as a substantially single rigid structure. Stilt walking using such a construction was in many ways similar to walking in a pair of oversized boots. Additionally, the spring mechanism added weight to the stilts, making it more difficult to execute fine movements or even remain in the stilts for long periods of time.
Articulation of both the footpad and the base pads considerably simplifies the stilts structure, as is taught by Ensmenger in U.S. Pat. No. 4,570,926. Known as the BIGFOOT(trademark) stilts, three support columns connect the foot holder and the base at hinged connections. In a departure from previous stilt designs, the base and the foot holder are divided into a xe2x80x9ctoexe2x80x9d portion and a xe2x80x9cheelxe2x80x9d portion by a hinge.
The three hinged columns thus define a pair of parallelograms, with the central column shared. Such a design provides stability to the wearer, whether the weight is evenly balanced between toe and heel, or where a particular movement results in a weight shift to either the heel or toe.
By providing this lightweight design, it was contemplated that such stilts would permit complex, controlled movements that were previously not possible using the prior designs. Such movements inherently subject the wearer to side loads, and to provide stability to resist such loadings, a calf brace is provided. To avoid requiring the user to over tighten the attachment strapping, a V-shaped bracing is used, with the leg of the user received within the upper portion of the xe2x80x9cVxe2x80x9d.
In the 926 Ensmenger Patent, the rear heel column is a double column that is joined at the bottom and angles outwardly to a pair of opposed attachment points along the outer edge of heel. The double column extends above these hinged attachments to form the calf brace. Unfortunately, this angled, two-piece construction with its side attachments pointing to the foot holder does not provide the strength of a single column heel brace. This vulnerability is particularly important during maneuvers on stilts that create particularly violent impact loadings on the heel portion, such as when landing after jumps.
This design shortcoming was addressed in the second Ensmenger Patent, No. 5,498,220, where the double-column heel support base attachment location is moved from the heel base to a horizontal support beam. A single column is then used to connect the heel base and the heel holder. The support beam extends from the single column heel to the middle, sole column, with hinges at both connections to permit its pivoting along with the heel base. In this manner a sound calf attachment is provided that helps to firmly attach the stilt walker to the stilts, yet the split brace is no longer a vertical load-bearing structure.
As was noted by Ensmenger, a toe-articulated stilt was considerably more natural in use than either the pole stilt or even the solid linear base of the DURA-STILT(copyright). However, just as certain styles of military marching where great force is applied to the heels resulted in heel and back problems, acrobatics and dance routines place great forces on the heels of stilt walkers. A need exists to modify the present stilts design to enable the stilts to absorb much of the vertical impact, and thereby assist in shifting the majority of such forces away from the heel.
It is an object of the present invention to provide a stilt having a multiple-articulating base. In this regard, an intermediate base segment is attached to both a toe and a heel segment in a manner that permits relative rotational movement between each segment. The length of the intermediate base segment is substantially equal to or greater than the length of either the heel or the toe segments, and by permitting the heel base to rotate relative to the intermediate base segment, walking forces are translated through the stilt base in a more natural manner.
It is a further object of the present invention to connect the multiple base segments of said stilt to a foot support or shoe utilizing a plurality of struts. In this regard a pair of front struts and a pair of rear struts are attached to the toe segment and the heel segment, respectively. A pair of strut braces is attached to each forward and rearward strut pair, providing lateral support, preventing lateral movement of the support struts. The strut braces are attached in a manner permitting relative angular movement between the struts and the strut braces. In this manner movement of the toe segment or the heel segment of the shoe is reflected in a like movement in the toe base or heel base.
A still further object of the present invention is to provide a stilt walker with enhanced lateral stability utilizing a securely anchored calf band. In this regard, a pair of support braces is attached to the rear struts and strut braces, as well as to the heel segment of the shoe. By such attachment at multiple lateral locations, side loadings placed on the calf band are vertically distributed over a number of individual members of the stilt.